1. Field of the Invention
The present invention relates to a socket for electrical parts which is located on a wiring substrate and accommodates an electrical part such as a semiconductor device (hereinafter, called an “IC package”) for executing a test of the electrical part.
2. Description of the Prior Art
Conventionally, the IC socket, which accommodates an IC package as “electrical part” removably, is known as the above-mentioned “socket for electrical part”.
The IC socket comprises a socket body which is mounted on the wiring substrate. The socket body comprises plural contact pins which electrically connect the IC package terminals and the wiring substrate. Moreover, the locater plate, which guards the lower terminal portions of the contact pins, is fitted on the lower side of the socket body. By the locater plate, the lower terminal portions of the contact pins are prevented from being bent while the IC socket is carried (see Japanese laid-open patent publication H3-155082).
The locater plate comprises plural ungues. On the other hand, the socket body comprises the projections. The locater plate can repetitively switch the position of itself between the top position and the bottom position (that is, the position lower than the socket body and near the lower terminal portion) based on the engaging state of the ungues and the projections. Consequently, the locater plate is held at the bottom position when the IC socket is not yet mounted on the wiring substrate (for example, while the IC socket is carried). On the other hand, when the locater plate is mounted onto the wiring substrate, the wiring substrate pushes up the locater plate and so the locater plate rises to the uppermost position.
However, in the case of conventional IC socket, the force for keeping the locater plate at the bottom-most position is not so strong when the IC socket is not yet mounted on the wiring substrate, because the ungues of the locater plate only engages with the socket body. Therefore, the locater plate is easy to rise toward the side of the socket body due to the oscillation of the IC socket and so forth, while the IC socket is carried. As a result, there is a case where the function of the locater plate (that is, the function to keep the lower terminal portions of the contact pins at the predetermined position) cannot be fulfilled sufficiently.
In addition, the conventional IC socket has a problem that the vertical motion of the locater plate cannot be executed smoothly, and so the operational feeling of the locater plate is not good. That happens because the conventional IC socket employs the structure of which the socket body is only engaged with the ungues of the locater plate.